Disposable diapers conventionally include a chassis having liquid permeable topsheet, a liquid impermeable backsheet and an absorbent structure sandwiched between the topsheet and backsheet. The chassis has a front body panel which, in use, extends over the stomach and front hip area of the user, and a rear body panel which, in use, extends over the back and the rear hip area of the user. Each of the body panels has a waist portion such that, when the diaper is fastened around the waist of the user, the waist portions provide a continuous encirclement of the user. In order to fasten the diaper around the waist of a user, a fastening system comprising fastening tabs is commonly employed. Fastening tabs may be provided on side panels which extend from lateral side edges of the diaper chassis.
As a user of a diaper moves about (i.e. eats, breathes, sneezes, crawls, walks, jumps, etc.), the circumference of the user's waist expands and contracts, which consequently results in the waist portions of the diaper being strained and relaxed. Repeated or exaggerated expansion and contraction of the waist portions can lead to permanent deformation of the waist portions, resulting in a slackening on the diaper around the waist. Particularly for active toddlers wearing diapers which already contain an insult, this often results in the diaper slipping down, thereby increasing the risk for leakage.
To reduce the risk of leakage when worn, a diaper should be provided with form-fitting properties at least in some areas. The form-fitting properties also contribute to an improved appearance of the diaper when worn by the user. Typically, one or both waist portions may contain an elastic waistband. Furthermore, the side panels on which the fastening tabs are provided may display elastic properties. However, elastic material is generally more expensive than non-elastic material and in many cases has poor breathability.
Even though conventional diapers may exhibit some form-fitting properties, the resistance to leakage is nevertheless increased if the diaper is not correctly fastened around the waist of a user.
When a user purchases an absorbent article it is not possible for him/her to predict how well the absorbent article stay in place when in use since test methods according to the prior art do not provide such information. Only test specimens cut from the fabrics that constitute an absorbent article are tested in known test methods. A disadvantage with testing only a test specimen of fabric is that an absorbent article usually comprises several different parts comprising various materials, which are used to fasten the absorbent article around a user's waist, such as adhesive tape, elasticated sections, elastic panels and other attached or integrated elements. It is therefore difficult to determine the net elastic and tensile properties of all of said parts/materials from an analysis of each part/material separately. Furthermore, the weight of an absorbent article and its contents are not taken into account in the tests carried out on a test specimen, even though the weight of an absorbent article and its contents will influence how well the absorbent article stays in place on a user.